1. Field of the Invention
The present invention relates to an orientation magnetization device and a magnet-embedded rotor.
2. Description of Related Art
There is known an interior permanent magnet synchronous motor (a so-called IPM motor) in which field permanent magnets are embedded in a rotor. Japanese Patent No. 4726105 discloses an orientation device that is used for manufacturing an IPM motor in which a resin material such as a bond magnet is embedded in a rotor as field permanent magnets by injection molding.
As disclosed in Japanese Patent No. 4726105, in the case where field permanent magnets are made of a resin material, the design flexibility in shape is enhanced, so that the surface area of the magnets can be increased, for example. This makes it possible to increase the magnetic flux interlinked with coils of a stator, and increase the torque of the motor. However, in the case where field permanent magnets are made a resin material, although the torque of the motor can be increased, there are still issues to be addressed in terms of reducing the torque variation in the motor.